The present invention relates to knee arthroplasty, and in particular, to an instrument and minimally invasive method for preparing a knee joint to receive the components of a knee prosthesis.
Orthopedic procedures for the replacement of all, or a portion of, a patient's joint have been developed over the last thirty years. Currently, the procedures used to prepare the bone and seat the implants are generally referred to as open procedures. For the purposes of this discussion, the term “open procedure” will refer to a procedure wherein an incision is made through the skin and underlying tissue to fully expose a large portion of the particular joint surface. In both total and unicondylar knee arthroplasty, the typical incision for an open procedure is about 8-10 inches long. After the initial incision in the skin, the internal wound may be enlarged to fully expose the areas to be prepared. While this approach provides surgeons with an excellent view of the bone surface, the underlying damage to the soft tissue, including the muscles can lengthen a patient's rehabilitation time after surgery. While the implants may be well fixed at the time of surgery, it may be several weeks or perhaps months before the tissues violated during surgery are fully healed.
Minimally invasive procedures have been developed to reduce both the incision size and the damage to soft tissue, thereby shortening a patient's rehabilitation time. One such procedure is described in The Zimmer MIS™ Quad-Sparing™ Surgical Technique for Total Knee Arthroplasty (NEXGEN® Complete Knee Solution), a surgical procedure for minimally invasive knee arthroplasty available from The Zimmer Institute of Warsaw, Ind. and attached hereto as Appendix A. Total knee replacement procedures generally involve the consecutive steps of making an incision and exposing the joint, resecting the distal end of the femur, resecting the proximal end of the tibia, sizing the femur and establishing external rotation, finishing the femur, sizing and finishing the tibia, performing trial reductions, and implanting the prosthesis components. Although effective, it is known that the joint space within which the surgeon must work is restricted and the cutting and removal of bone can be a challenging task when working in this small joint space.
There is a need for a method and an instrument that can be used to create additional space at the surgical site and facilitate the steps in the preparation of the knee joint to receive the components of a knee prosthesis